The search resumed this morning for a missing 27-year old Philomath man, who disappeared while climbing Mt. Adams by himself on Sunday.

KGW-TVDerek Mamoyac

Deputy Alan Klise with the Yakima County Sheriff's office said that some searchers spent the night at the trailhead where they found Derek Mamoyac's car.

Additional volunteers are to join the effort today to search the mountain's southeast side, Klise said. By early afternoon today about 50 volunteers were searching the mountain.

Mamoyac left Portland Saturday night and planned to reach the summit of the 12,276-foot Cascade volcano with an early-morning start Sunday, searchers said. Mamoyac aimed to reach the summit and descend in a day with a minimum of gear.

Another climber told deputies that he saw Mamoyac at about 9:30 a.m. on Sunday at 9000 ft. altitude, just above a high plateau called the "lunch counter," a popular camp spot for those ascending the mountain.

The climber said Mamoyac was heading up toward the summit. They spoke briefly.

"As far as we know, that was the last person who saw Mamoyac that day," said Sgt. Gerrold Towell of the sheriff's office. The sheriff's office is not releasing the identity of the other climber at this time, Towell said.

Mamoyac was reported missing Monday when he failed to show up at his job at a Corvallis Fred Meyer store, said Steve Rollins, a veteran climber and spokesman for Portland Mountain Rescue.

A friend, Robert Dennis, said Mamoyac had rented equipment that included crampons and other climbing gear.

"It wasn't like he just went off and ran up the mountain," Dennis said. His friend hikes and climbs by himself often, he said.

Rollins said that Mamoyac had climbed mountains in California and Oregon, but that this was his first attempt to reach Adams' summit.

"It's a little late in the season to take such a minimalist approach in my opinion,'' Rollins said. "You're taking a lot of risk."

According to officials with the Gifford Pinchot National Forest, while the climb is not considered technically difficult, it takes from six to eight hours of climbing nearly 6,700 feet of vertical snow and rock to reach the summit.

"What appears to be a non-technical route can change drastically during these storms,'' a climbers guide on the forest's Web site states. "Your safety will be the result of your preparation and good judgment. Climbers should always prepare for bad weather and an extended stay on the mountain.

"Sudden snowstorms can occur above 6,000 feet elevation at any month of the year."

Frost advisories and freeze warnings were in effect Saturday and Sunday in much of Oregon and Washington, where temperatures dipped into the 20s and 30s. Temperatures at higher elevations on Mount Adams were even colder, weather service officials said.